Sorry. I misread your post. I agree with the others to make sure that you always safely eject your reader before disconnecting the USB cable. On my Mac I have to eject two items: both the Reader and Setup as separate "disks".

You don't have to actually eject Setup as you won't be reading or writing from it.

It may not be officially labelled as Eject but Safely Remove Hardware is the same thing and yes it will cause issues when you don't eject or safely remove the reader properly from the computer. Ejecting/Safely Removing is built in as part of Windows not the device.

The same thing happened to me once with my T1 when I just pulled the plug.

I have caused a problem with my 505 when I pulled the plug without ejecting. So yes, ejecting/safely removing hardware is what should always be done.

I made sure the simple copy procedure was complete.. I have a suspicion that something else is going on when windoze accesses the device... no matter I shall avoid plugging it in unless absolutely necessary.. I had a look at the running processes on the laptop but there was nothing there that seemed strange.. ah well

It's not plugging it into the USB that's a potential problem. It's just pulling the plug without safely removing it is a potential problem.